Kristina Hamberg

Salivary IgA in minor-gland saliva of children, adolescents, and young adults.

According to previous studies, minor glands produce about 35% of the total salivary immunoglobulin A (salivary IgA). The age-dependent increase in whole-saliva salivary IgA concentrations has been studied extensively, but we found no published reports comparing the minor-gland saliva concentrations of salivary IgA in children, adolescents, and adults. In this study we measured the concentration of salivary IgA in saliva from the labial and the buccal minor glands of children, adolescents, and adults. Three age groups donated saliva for analysis: 3-yr-old children, 14-yr-old adolescents, and 20- to 25-yr-old adults. Minor-gland saliva was collected on filter paper and unstimulated whole saliva was collected by draining into a tube, and the salivary IgA concentration was determined by ELISA. The salivary IgA concentration in labial saliva was significantly lower among 3-yr-old children (0.037 mg 100 ml(-1), SD = 0.035) than among 14-yr-old adolescents (0.126 mg 100 ml(-1), SD = 0.128) and adults (0.128 mg 100 ml(-1), SD = 0.13). The 3-yr-old children also had significantly lower whole-saliva salivary IgA values compared with the other age groups (0.09 mg 100 ml(-1), SD = 0.091; 0.179 mg 100 ml(-1), SD = 0.149; and 0.170 mg 100 ml(-1), SD = 0.099, respectively). This increase in salivary IgA concentrations with age might reflect a developing immune response in the growing child.

Oral Administration of Lactobacillus plantarum 299v Reduces Cortisol Levels in Human Saliva during Examination Induced Stress: A Randomized, Double-Blind Controlled Trial

Objective. To clarify the effect of Lactobacillus plantarum 299v on the salivary cortisol and salivary IgA levels in young adults under examination stress. Design. Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification of L. plantarum 299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing. Results. A significant difference in cortisol levels was found between the treatment group and the placebo group (P < 0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group (P < 0.001). No significant changes were found for salivary IgA. Conclusion. A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study is NCT02974894, and the study is registered at ClinicalTrials.gov.

Lactobacillus reuteri supplements do not affect salivary IgA or cytokine levels in healthy subjects : A randomized, double-blind placebo-controlled, cross-over trial

Abstract Objectives: To evaluate the effect of daily ingestion of probiotic lactobacilli on the levels of secretory IgA (sIgA) and selected cytokines in whole saliva of healthy young adults. Materials and methods: The study group consisted of 47 healthy adults (18–32 years) who volunteered for a randomized, double-blind, placebo-controlled, cross-over trial after informed consent. During intervention, the subjects ingested two lozenges per day containing two strains of the probiotic bacterium Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) or placebo lozenges. The intervention and wash-out periods were 3 weeks. Saliva samples were collected at baseline, immediately after each intervention period and 3 weeks post-intervention. ELISA was used to measure sIgA and luminex technology was used to measure the interleukins (IL)-1β, IL-6, IL-8 and IL-10. For statistical analyses a mixed ANOVA model was employed to calculate changes in the salivary outcome variables. Results: Forty-one subjects completed the study and reported a good compliance. No significant differences in the concentrations of salivary sIgA or cytokines were recorded between the L. reuteri and placebo interventions or between baseline and 3 weeks post-intervention levels. No side- or adverse effects were reported. Conclusions: Supplementation with two strains of the probiotic L. reuteri did not affect sIgA or cytokine levels in whole saliva in healthy young adults. The results thereby indicate that daily oral supplementation with L. reuteri do not seem to modulate the salivary oral immune response in healthy young subjects (ClinicalTrials.gov NCT02017886).

Collagen degradation and preservation of MMP-8 activity in human dentine matrix after demineralization.

OBJECTIVE Dental caries is a process driven by acids produced by oral microorganisms followed by degradation of the dentine collagen matrix by proteolytic enzymes. Matrix metalloproteinases (MMPs) have been suggested to contribute to caries by degrading collagen. The aim of this study was to develop a method for generating demineralized dentine matrix substrate (DDM) maintaining MMP-8 bioactivity and no interference with later assays. Such a substrate would allow study of the effects of various treatments on MMP-8 activity and collagen degradation in demineralized dentine. DESIGN Human dentine was powderized in a tissue grinder and frozen (-80°C). The powder was demineralized in dialysis tubes, using EDTA or acetic acid. The demineralized dentine matrix (DDM) was harvested and analyzed for collagen content using SDS-PAGE. The DDM was subsequently suspended in PBS or TESCA buffer. Protein, MMP-8 (ELISA) and collagen (HYP) was analyzed directly or after 1 wk. RESULTS EDTA or acid demineralization of dentine using dialysis yielded a substrate rich in collagen coupled with preserved MMP-8 activity. Collagen degraded in room temperature, assessed by higher HYP amounts in the soluble fraction of DDM after one wk, indicating that the methods used preserved active DDM-components after the demineralization process. CONCLUSIONS The presented demineralization methods both provided insoluble DDM substrates suitable for further intervention studies. However, it was found that the substrates differed depending on the demineralization method and buffers used. This needs further study to find an optimal technique for generating DDM with retained proteins as well as enzymatic bioactivity.